Assightok



E. P. OGDEN. TUNNEL KIL N.

APPLICATION FILED NOV- 5. 1 920.

Patented June ll/6741115! A mgr/1111115!!! A UNITED STATES PATENT OFFICE.

ELLSWORT'H 1P. OGDENyOFCOLUMBUS. OHIO, ASSIGNOR 'EO JGHN B. OWENS, 0F ZANESVILLE, OHIO.

TUNNEL KILN.

Specification of Letters Patent.

Patented June 6, 1922.

Application filed November 5, 1920. Serial No. 422,000.

T 0 all whom it may concern:

Be it known that I, ELLSWORTH P. (Japan, a citizen of the United States, residing at Columbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Tunnel Kilns. of which the following is a specification.

This invent-ion relates to tunnel kilns and, more particularly, to a means and method whereby flashing conditions at high temperatures may be obtained, for the accomplishment of salt glazing and other special heat treatments without disturbing the normal pyro-chemical conditions in the lower-heated parts of the kiln.

My object is to provide means, and a method, for the production of the desired kiln atmosphere conditions in the maximum temperaturezone, of a tunnel kiln wherein the tunnel which has not attained a sufiiciently high temperature to render it susceptible to the desired chemical treatment.

The object aforesaid is accomplished by the provision of a fan or an auxiliary stack or stacks or other draft-inducing means acting on the firing zone of the tunnel at any suitable point or points, preferably near the zone of maximum temperature, there being suitable damper control, with means where by the damper or dampers employed for that purpose may be operated substantially at the same time with the operation of a damper in the main draft outlet, and the method therein involved.

To accomplish flashing, reducing conditions will be produced by supplying excess fuel and limiting the air supply to the combustion chambers. Salt glazing conditions can be produced by the introduction of salt intothe combustionchambers and flooding the tunnel with the sodium chloride vapors which unite with the silica in the clay wares undergoingfiring and thus produce the salt glaze of commerce. Any other desired chemical treatment of the clay wares may be accomplished by 'fiooding the Y tunnel; with gases or vapors of the desired nature.

The important feature of my invention is that themeans and method involved provide for the removal of all such special gases or vapors from the tunnel before they have an opportunity of coming in contact with any ware in the tunnel which has not attained a sufficiently high temperature to render it susceptible to the desired chemical treatment.

While I have disclosed in the accompanying drawings, and hereinafter describe, certain embodiments of my invention, this is done by way of illustration and not for the purpose .of limiting the scope of the invention to these particular embodiments as I am well aware that my improved means and method may be carried out in other forms without departing from the essential principles thereof.

In the accompanying drawings:

Figure 1 is a plan view, partly in section; I

Fig. 2 is a cross section on Fig. 1; A

Fig. 3 is a cross section on line 33, Fig. 1; and

Fig. l is a cross section on line 4l.--4, Fig. 1.

My improvements are shown as embodied in a tunnel kiln of the multiple combustion chamber and multiple firing zone type invented by John B. Owens and disclosed in certain applications filed by him, in so far as it embodies a preheating'zone 1, multiple burning or firing zone 2 and cooling zone 3, there being multiple furnaces or combustion chambers 41, of which there may be any desired number, arrangedin pairs, each pair having a continuous arch 5 constituting the crown and outer walls of the combustion chambers. The combustion chambers are fired in the direction of their lengths, that is, parallel to the tunnel. The stack which is shown at 6 is connected to the interior of the tunnel by flues 7 which areprovided with line 2-2,

dampers 8 constructed and arranged for with any particular type or construction of tunnel kilng I provide an auxiliary stack or stacks, or draft-inducing means connected with the tunnel at a suitable point or points of tie firing zone 2 but preferably near the zone of maximum temperature. pair of such stacks is shown at 11, 12, which communicate with the interior of the tunnel through ducts or lines 13, 1 The stacks 11, 12 are provided with dampers 15, 16 adapted for quick opening and closing.

It is within the spirit of my invention to employ separate operating means for opening and closing the dampers 8 on the one hand, and the dampers 15, 16, on the other hand and to time the operation so that it will be simultaneous. I prefer, however, to connect the dampers 8 with the dampers 15, 1.6 by hand lines 17 running over pulleys or other supports 18 so that by simply pulling upon these hand lines, simultaneous opera-- tion will be effected.

Under normal conditions the dampers 15, 16 will be closed and the draft through the kiln will be effected by the stack 6 or a fan or whatever draf -inducing means is used, the dampers 8 being operated as desired, as usual in draft control.

To utilize my invention for any of the purposes hereinafter set forth, the operation is as follows: At regular intervals during the firing process and logically during the period just preceding the movement v of the cars in the tunnel, the main draft dampers 8 are closed and the auxiliary dampers 15, 16 are opened by pulling on the hand lines 17. This action is accompanied by the generation of the desired kiln atmosphere conditions in the maximum temperature zone, whether this condition be for the purpose of flashing, salt glazing, or other chemical treatment. It is to be understood that the dampers 15, 16, affordmeans for releasing from the kiln, through the lines 13, 14: and the stacks 11, 12, any special gases or vapors which have been introduced in the kiln for the purpose of special treatment of the ware, such removal being brought about before the gases or vapors come in contact with any ware that has not attained a sufficient temperature to render it susceptible to the desired special treatment. The draft being cut off through the stack 6, the gases and-vapors used for special treatment cannot pass down the tunnel far enough toward the entry end thereof to affect ware which has not risen to the proper temperature to warrant the special treatment in question. When the hand lines 17 are operated to close the dampers 15, 16, the operation opens the dampers 8 and the normal draft through the kiln is restored.

What I claim is:

l. A. tunnel kiln provided with a main stack or fan and also having an auxiliary stack or fan independent thereof by which special gases and'vapors which havebeen introduced into thekiln for special purposes may be removed therefrom without resort being had to the means for inducing the main draft.

2. A tunnel kiln provided with a main stack or fan and also having an auxiliary stack or fan independent thereof acting on the firing zone of the kiln whereby special gases and vapors which have been introduced into the kiln for special purposes may be removed from the firing zone without resort being had to the means for inducing the main draft before said gases or vapors have the opportunity of coming in contact with ware in other parts of the kiln.

3. A tunnel kiln provided with a main stack or fan and also having an auxiliary stack or fan independent thereof by which special gases and vapors that have been introduced into the kiln for special purposes may be removed therefrom, and draft controlling means for the respective draft-inducing means aforesaid, whereby the draft may be allowed to pursue its normal course, or, be taken off by the auxiliary draft-inducing means to the exclusion of the main draft inducing means.

4. A. tunnel kiln provided with means for producing draft therein, and also having auxiliary draft-inducing means whereby special gases and vapors which have been introduced into the kiln for special purposes may be removed therefrom, and controlling devices for the draft producing means and auxiliary draft inducing means which are subject to a common control whereby one of said means may be rendered active when the other is inactive.

5. A tunnel kiln provided with a stack or fan for causing the usual draft therein, and also having an auxiliary stack or fan actingon the firing zone of the kiln whereby special gases and vapors which'have been introduced into the kiln for special purposes may be removed from the firing zone before they have the opportunity of coming in contact with ware in other parts of the kiln, and controlling devices for the aforesaid'main and auxiliarydraft-inducing means which are subject to a common control whereby one of said means may be rendered active when the other is inactive. I

6. The'method of operating a tunnel kihi, consisting in effecting flashing conditions, salt glazing,-or other special heat treatments while the normal draft in the kiln is shut off, and taking off from the kiln the special the kiln which has notreached a condition adapted for the specialtreatment. I

7. The method ofoperating a tunnel kiln, consisting in effecting flashing conditions,

salt glazing, or other special heat treatments While the normal draft in the kiln is shut 0H. and taking off from the heat Zone of the kiln the special gases or vapors introduced therein, by means other than the normal draft-inducing means during the time the normal draft is shut 0ft, thereby preventing the special gases or Vapors from passing beyond the heat zone and coming in contact with ware which has not acquired a sufii- 10 ciently high temperature adapting it for the special treatment.

In testimon whereof I aflix my signature.

LLSWORTH P. OGDEN. 

